Nitrox instead of air for lower DCS risk?

[diverdown78]

I'm an old toad, but in good shape. I want to minimize age-induced risks of DCS. I've been diving on air, with depths mostly in the range of 60 to 100 feet. I'm usually a hoover, so I usually have less remaining air time than the no-deco limit, so I don't need nitrox for more bottom time (yet).

When we were talking about managing my risk of DCS, my LDS operator suggested switching from air to nitrox. This is not a scam to charge me more for fills, BTW. If I were to adopt EANx32 as my standard mix, my normal depths would be comfortably below its MOD. Moreover, using EANx28 would cover me for all recreational depths. I'd use nitrox on "shallow" dives, too.

The suggestion seems logical to me. There would be less nitrogen entering my tissues, therefore less to off-gas, therefore fewer bubbles and cascades, and reduced chance of "subclinical DCS" (NetDoc's term for post-dive tiredness and lethargy).

What do you think? In general, would breathing nitrox instead of air reduce my risk of DCS?

yes...if you still dive on air tables

 

[Rolodive]

The situation which people seem to ignore is the fact that dive times are often not limited by no-stop times nor available gas in the cylinder. In many tourist spots, most notably in my mind a recent trip to dive Hawaii, dive time has more to do with the desire of the divemaster to get back to shore and on with his/her social life. Here in laid back St. Croix they tend to shoot for 40-50 minute dives, but in Hawaii we found we were getting hustled back to the boat after just 25-30 minute dives. The recently pubescent boat crews and dive staff are underpaid, overworked, and seldom have their heart in being under water yet again for the 28th time this week. In that scenario, you are way better off with nitrox cause when you dive with this kind of operator, you're going to dive the same amount of time and same depths no matter what you're breathing, so you will in fact decrease your nitrogen loading with nitrox.

 

[Screwbag]

Just to toss in my 2 cents here...
Several of the Commercial diving companies around scandinavia are switching to nitrox for their daily gas use...as it increases their insurance safety profile...at least thats what they tell me...

 

[TropicRat]

BT:

Been around the track a time of two myself.

It's a no-need to engage brain before shifting into drive. Do it before your next dive!!

For older divers Nitrox is the ticket. In your case go by the old saw and treat it like
it was air.

Reduced DCS and the increase of O2 on old things is highly beneficial.

 

[DevonDiver]

The easiest way to to comprehend the potential benefits of nitrox, is by considering it in terms of the EAD (equivalent air depth) of the dive profile.

Nitrox allows you to conduct a dive to depth X, whilst only absorbing nitrogen as if you were at depth Y.

This means that for two identical dives, the nitrox user will have less nitrogen saturated into their tissues. Less saturated nitrogen equals lower risk of DCI.

However, if the nitrox user took advantage of the shallower EAD, as tool for increasing their bottom time, compared to an air diver at the same depth, then they would lose that safety benefit.

They would absorb nitrogen slower, but would do so for a longer time....so the end result would be the same.

 

[Wayan]

I'm an old toad, but in good shape. I want to minimize age-induced risks of DCS. I've been diving on air, with depths mostly in the range of 60 to 100 feet. I'm usually a hoover, so I usually have less remaining air time than the no-deco limit, so I don't need nitrox for more bottom time (yet).

When we were talking about managing my risk of DCS, my LDS operator suggested switching from air to nitrox. This is not a scam to charge me more for fills, BTW. If I were to adopt EANx32 as my standard mix, my normal depths would be comfortably below its MOD. Moreover, using EANx28 would cover me for all recreational depths. I'd use nitrox on "shallow" dives, too.

The suggestion seems logical to me. There would be less nitrogen entering my tissues, therefore less to off-gas, therefore fewer bubbles and cascades, and reduced chance of "subclinical DCS" (NetDoc's term for post-dive tiredness and lethargy).

What do you think? In general, would breathing nitrox instead of air reduce my risk of DCS?

You need to do more than to just change to nitrox to reduce the risk
Use air tables instead of Nitrox tables
change dive profiles
reduce bottom times (considerably)
Do not dive as deep
increase surface interval times (it appears most people us the 1-1 1/2 hour )
hydrate hydrate some more

Combining these together these MAY reduce the risk (but not necessarily substantially) but as with anything in life there is no guarantees. Have seen people with what seems to be perfectly sound profiles (air / and or EANX)
end up with DCS / DCI.

 

[PhatD1ver]

so, as a newby, who is going to get nitrox trained end of the month on my dive trip... let me ask this... in April I did a trip and we did three days of three dives a day... by end of day three, I was bonked, a little light headed, and minor headache, and splotchy red/hivey stuff on my arms (but not chest)... clearly showing some signs of that 'subclinical signs of DCS' and cancelled my morning dives for Day 4 that would have still left me 24 hours before I flew back the next day (Day 5) ...

The dive computer was tracking all this, I was fully loaded with nitrogen when I left the water on dive #9, in theory I'd burn plenty off in 16 hours, but since I'm older, Phatter, and haven't got much experience under my belt yet, I also figured I might just off-gas a little slower than some....

Finally, here is the question... last day, all dives were to 20 meters or less, if I had switched to Nitrox all day on Day 3, theoretically, with the same dive plans and bottomtime, I should have had less nitrogen in my system... YES?

I'm thinking of following the common thought here and just going to 100% nitrox going forward when I have multidive days. Boat diving, it's a pain for the operator to prep three tanks for me.. TOUGH.

 

[DocVikingo]

Finally, here is the question... last day, all dives were to 20 meters or less, if I had switched to Nitrox all day on Day 3, theoretically, with the same dive plans and bottomtime, I should have had less nitrogen in my system... YES?

Yes, but whether the reduction in nitrogen would be enough at this point to meaningfully reduce the risk of DCS is questionable.

And speaking of questionable, the development of mild light headedness, minor headache & and splotchy red/hivey rash on the arms is by no means definitive of DCS--mechanisms other than breathing compressed air could have caused these.

Finally, as a matter of proper terminology, if these were in fact signs/symptoms of DCS, they wouldn't be "subclinical"--after all, they are evident/showing/manifest, aren't they? : )

I'm thinking of following the common thought here and just going to 100% nitrox going forward when I have multidive days.

I'm not sure you'd want to do that as breathing "100% nitrox" [which means 100% oxygen/0% nitrogen] would very likely send you into convulsions before you descended very far down into the water column.

You'll learn all about this in your nitrox training class scheduled for end of this month.

BTW, you're going to adore Anilao.

Have a dive circus.

Cheers,

DocVikingo

 

[Compressor]

A great discussion with top notch advice given in this thread. I'll look for similar thread on trimix.